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Environmental Research

PTR-MS for ultra-sensitive real-time monitoring of air pollutants

IONICON PTR-MS systems are well established tools in environmental research. Their fast response-times and ultra-low detection limits help researchers all over the planet to better understand the world we live in.

High resolution monitoring of roadside-air VOCs

The IONICON PTR-TOFMS series features not only a very low detection limit for most common VOCs but delivers results with a very high mass resolution and quantification of the whole unlimited mass range in one scan. This allows our customers to discriminate isobars and get substantially more information from the collected data.

The graph on the left side shows a very good example of very low concentrated isobars that were detected using a PTR-TOF 8000. Both compounds have the same nominal mass and cannot be distinguished using a quadrupole bases instrument. Using a PTR-TOF, however, we were able to seperate and identify them as C3H6O2 ( e.g. acetic acid methyl ester or and formic acid ethyl ester) at 75.0446 and C4H10O ( e.g. dimethylethanol) at 75.081.

Mobile PTR-MS solutions

Our instruments are perfectly suited for field campaigns, as a lot of scientists have successfully proven over the last decade. Among them, Prof. Berk Knighton, Montana State University, has installed an IONICON PTR-MS in a mobile lab to monitor engine exhaust in real-time, "chasing" single vehicles in Mexico City Metropolitan Area's traffic. It was shown that the results differ according to vehicle condition, fuel quality, and driving behavior.

Experience this experiment in an illustrative video sequence (15 Mb, quicktime, courtesy of Prof. Knighton). In the video you will see a picture of the vehicle being monitored in the upper left hand. On the bottom you will see the evolution of two signals: (1) CO2, a combustion tracer to verify that the mobile lab is intercepting the vehicles exhaust plume; and (2) PTR-MS signal at m/z 57, a fragment from MTBE, an additive in Mexican fuel. In the upper panel a correlation scatter plot of the m/z 57 signal (in ppbv) versus the CO2 concentration is shown. The slope represents the emission ratio.

VOCs in the troposphere

Road traffic contamination is quantifiable even in over 3000 meters altitude. This has been successfully demonstrated in early PTR-MS studies.

Tropospheric VOCs at higher altitudes have been measured in in long-term investigations at the top of the Sonnblick, Austria (3100 m) and in flight experiments up to 12 km altitude above the rain forest in South America. Meteorologists have calculated back-trajectories and thus more information on the measured VOCs could be gathered. Moreover, the PTR-MS analysis were validated.

PTR-MS for flight campaigns

IONICON has a lot of experience in creating customized solutions for special tasks. We offer customized PTR-MS solutions for installation in airplanes and other vehicles.

An IONICON PTR-MS has been used at a project called "Aircraft Measurements of Highly Reactive Volatile Organic Compounds Using Proton Transfer Reaction Mass Spectrometry (PTR-MS) During TexAQS II". It shows that our systems can monitor VOCs online, in a very high time resolution and nevertheless with a very low detection limit. Download the final report!